I am new to burning coal and installed a koker 160 a few months ago and it seems to be burning fine my draft is between .02 and .03 as per the instructions my problem is sometimes there is a strong sulfur oder i have 2 co detectors neither have alarmed the other day i noticedwhat appears to be an area between the stove and the hopper where fly ash (a white powderey substanc) seems to be escaping it is an area about 3 inches long in the center of the width of the hopper all my other joints are sealed with high temp RTV i dont believe this is normal should this area be sealed or did i do something wrong HELP

As already stated it's time to crack open the flue pipe if you don't have a 'T' to access it and vac out the elbows and horizontal sections. After a couple months and running a couple tons through the unit fly ash will build up and cut down on the exhaust path. Good to hear you have the CO monitors!!

Also, if the inside of the stove hasn't been brushed down it is a good time to do that since it will improve your heat transfer from the firebox.

A koker owner will probably check in and let you know if there are any particular places to make sure you brush out.

Where the coal hopper rests inside the back of the stoker unit, it does not need to be sealed. I believe there is a fiber gasket in the back of the stove where the stoker assembly and its associated plate bolts to the stove. I am not sure where you are putting RTV sealant on the stove. The stove should have come from Keystoker ready to burn. Everything that is sealed (most notably, the coal bed plates) at the factory should be the only thing that needs to be sealed. Can you post some pictures of the area you are talking about? If your draft is poor or you have too much combustion air blowing into your stove, CO can work its way through the coal bed in the stoker and out your hopper, but I can't imagine fly ash would be able to follow this route and end up collecting on the outside of the stove body.

The only other thing I can think of is that you have too much air blowing into the stove which may periodically cause you too lose your draft. Especially with the warmer weather coming, you need to close off the plate on the combustion air fan down to maybe 1/4 open or less.

Rule of thumb - if you have burn by-products (smells, gases or fly ash) outside your stove, you have draft problems. With a constant good draft in your flue, the stove will ALWAYS draw air into itself. Most of this comes from the combustion blower, but any other openings that may exist (notably, at your doors) will also allow house air to be drawn into the stove and out the flue pipe.

Make sure to vacuum under the grates. If you don't get enough air from the cumbustion blower, the stove will get it from the hopper. The fire may start to burn up into the hopper. This happened to me and I did not see the hot coals from above the hopper. But I felt the heat under the hopper by touch.

Unless I missed it you didn't say if your going into a chimney, direct or power vented. There are a few places that are difficult to seal & if your getting a smell & a little flyash at times it could just need a cleaning if you have been running hard for a few months without. A picture if possible would help.